Melanoma Sites & Solar Radiation
Most cases of melanoma are linked to excessive exposure to ultraviolet radiation (UVB) in the sunlight. As a result, the most commonly involved sites are head and neck region and lower extremities in non-Hispanic Whites with fair complexion and tendency to excessive freckling and developing sunburns easily.
Melanin pigment protects against the damaging effects of solar radiation. As a result, melanomas are uncommon in dark-skinned races, except for Albinos and in sites lacking pigment such as palms, soles, subungual region, and mucous membranes (mucocutaneous junction of oral and nasal cavities).
Among the melanoma subtypes, superficial spreading melanoma is related to sporadic intensive exposure to solar irradiation (e.g. sporadic sunbathing). With lentigo malignant melanoma, the risk is related more to life-long chronic exposure to sunlight (e.g. outdoor workers).